Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 15,912	$ 11,461	$ 30,378	$ 19,434
Other comprehensive income (loss):
Foreign currency translation adjustment	167	(30)	141	(108)
Tax benefit (provision)	(44)	11	(40)	36
Comprehensive income	$ 16,035	$ 11,442	$ 30,479	$ 19,362

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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